As a result of stricter regulations for automotive emissions, it was desired to design a testing apparatus and procedure for testing emissions control devices. Historically, actual internal combustion engines have been used for such evaluations. However, the use of a real engine for long term testing can be inconsistent, maintenance intensive, and expensive to operate. In addition, a real engine does not conveniently permit the separate evaluation of individual variables, such as the effects of various constituents of fuel and oil.
U.S. Patent Pub. No. 2003/0079520, entitled “Method and Apparatus for Testing Catalytic Converter Durability” and U.S. Patent Pub. No 2004/0007056 A1, entitled Method for Testing Catalytic Converter Durability”, both describe an exhaust flow simulation system. The system comprises a fuel-combustive burner with an integrated, computerized control system. The system realistically simulates the flow of exhaust gas from an engine under a variety of load conditions.
For testing emissions control devices designed for diesel engines, a burner system can provide an effective and practical approach to perform aging and evaluation work. It provides accurate control of the air-to-fuel ratio (AFR) and exhaust temperature. In addition, it can more easily achieve elevated temperatures and a wider band of AFR control than can be achieved with engine-based systems. U.S. patent application Ser. No. 10/917,230, to Anderson, et al, entitled Testing Using Diesel Exhaust Produced by Non Engine Based Test System, now U.S. Pat. No. 7,212,926, and assigned to Southwest Research Institute, described a burner-based exhaust gas simulation system used to simulate exhaust from a diesel engine.